vstart: Update apache conf to run against apache 2.4

Tested with ./vstart.sh -r -l -n -x was not working anymore on ubuntu 13.10 as it uses apache 2.4, which one introduces changes in configuration and default options requierement.

Might need testing on previous versions of apache.

Signed-off-by: Christophe Courtaut <christophe.courtaut@gmail.com>